Privilege escalation in Linux kernel SNMP NAT module

1) Privilege escalation

EUVDB-ID: #VU17878

Risk: Low

CVSSv3.1: 7.9 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2019-9162

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Exploit availability: No

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to array index error in SNMP NAT module (net/ipv4/netfilter/nf_nat_snmp_basic_main.c) when parsing ASN.1-encoded payloads in SNMP messages. A local user can set up new network namespaces that invoke iptables configuration and triggers SNMP translations, cause out-of-bounds read and write operations and execute arbitrary code  on the system with elevated privileges.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Linux kernel: 4.14.19 - 4.20.11

External links

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=c4c07b4d6fa1f11880eab8e076d3d060ef3f55fc
http://www.securityfocus.com/bid/107159
http://bugs.chromium.org/p/project-zero/issues/detail?id=1776
http://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.25
http://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.20.12
http://github.com/torvalds/linux/commit/c4c07b4d6fa1f11880eab8e076d3d060ef3f55fc

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.